UNIVERSITY   OF   CALIFORNIA        AGRICULTURAL  EXPERIMENT  STATION 

BENJ.    IDE    WHEELER,    PRESIDENT 

COLLEGE    OF    AGRICULTURE  THOMAS  FORSYTH   HUNT>  Dean  anq  D|rector 

nrnuri    c"w  H.  E.   VAN    NORMAN,    Vice- Director    and    Dean 

btKI\tLtY  UNIVERSITY    FARM    SCHOOL 

CIRCULAR  No.   126 
March,  1915 


SPRAYING  FOR  THE  GRAPE  LEAF-HOPPER 

BY 

H.  J.  QUAYLE 

Injury. — The  grape  leaf-hopper  (Typhlocyba  comes,  Say.)  is,  at 
the  present  time,  probably  the  most  important  insect  pest  of  the  vine 
in  California.  While  greater  actual  damage  has  been  done  to  the  vine- 
yard interests  by  the  phylloxera,  this  injury  is  largely  past  because 
of  the  replanting  on  resistant  stock  in  most  sections  where  the  phyl- 
loxera was  formerly  destructive.  The  injury  by  the  grape  leaf -hopper, 
on  the  other  hand,  has  really  increased  because  of  the  greater  acreage 
planted,  which  has  favored  the  increase  of  the  insect. 

Leaves  with  a  mottled  aspect  of  gray  and  green  are  the  first  indi- 
cation of  hopper  injury.  As  the  feeding  continues,  the  whole  surface 
of  the  leaf  becomes  at  first  silvery,  and  later  yellow  and  brown,  when 
it  finally  drops  from  the  vine.  Leaves  thus  affected  occur  most  com- 
monly about  the  crown  of  the  vine,  though  in  cases  of  severe  injury 
nearly  all  the  leaves  will  show  this  effect.  Many  of  the  leaves  may 
drop  off  or  become  functionless,  as  early  as  June  or  July,  and  this 
loss  of  foliage  prevents  the  berry  from  maturing  properly.  The  lack 
of  full  foliage  to  the  end  of  the  season  also  prevents  the  canes  from 
ripening  normally  for  next  year's  wood.  The  buds  fail  to  develop 
in  the  following  spring,  and  thus  the  vine  may  be  more  or  less  per- 
manently stunted  in   growth  in  severe  cases  of  hopper  injury. 

While  injury  as  above  described  occurs  in  some  sections  or  some 
vineyards  nearly  every  year,  such  injury  does  not  occur  universally. 
It  is  only  when  the  hoppers  become  excessively  numerous  that  enough 
injury  is  done  to  warrant  treatment. 

Distribution. — The  grape  leaf -hopper  occurs  in  numbers  sufficient 
to  be  a  pest  only  in  the  Sacramento,  San  Joaquin  and  Imperial  valleys. 
It  rarely  becomes  injurious  in  the  coast  valleys  or  the  grape  sections 
in  Southern  California,  aside  from  the  Imperial  and  the  Coachella 
valleys. 

Seasonal  History. — The  grape  leaf-hopper  passes  the  winter  as  an 
adult  insect,  which  may  feed  on  various  plants  growing  in  the  vine- 


yard  or  vicinity  during  the  warmer  weather.  During  cold  or  wet 
weather,  it  remains  under  leaves  or  rubbish,  or  low  down  on  the 
growing  plants  on  which  it  feeds.  When  the  vine  comes  into  leaf  in 
the  spring,  the  hopper  leaves  its  varied  winter  food  plants  and  feeds 
exclusively  on  the  grape  leaves  until  they  fall  in  the  autumn. 

The  young  hoppers  or  nymphs  begin  to  hatch  about  May  1st  in  the 
Fresno  section,  a  little  later  in  the  Lodi  and  Stockton  sections,  and 
two  or  three  weeks  earlier  in  the  Imperial  Valley.  The  eggs  require 
from  eight  to  twelve  days  to  hatch,  and  eighteen  days  are  required 
to  bring  the  young  to  maturity.  About  one  hundred  eggs  are  laid  by 
each  female.  The  young  of  the  first  generation  begin  appearing  in 
May,  and  the  young  of  the  second  generation  in  the  latter  part  of 
June.     There  are  thus  two  generations  of  the  hopper  in  a  season. 

Control  of  the  Overwintering  Adults.— Turning  sheep  into  the 
vineyard  in  the  fall  to  eat  the  leaves  results  in  causing  the  hoppers 
to  go  to  their  winter  food  plants  a  little  earlier,  and  also  deprives  them 
of  shelter  in  the  accumulation  of  leaves  in  the  vineyard.  A  clean  vine- 
yard in  the  winter  season  has  fewer  hoppers  than  one  in  which  there 
are  more  or  less  green  growth  and  bunches  of  dry  grape  leaves. 

Plowing  in  the  early  spring  and  turning  under  the  green  growth 
and  dry  leaves  does  not  destroy  the  hoppers,  but  does  drive  them  to 
the  borders  or  to  neighboring  fields.  The  result  then  of  both  sheeping 
and  early  plowing  is  to  drive  the  hoppers  elsewhere  for  food  and 
shelter,  but  there  is  no  assurance  that  many  of  these  will  not  return 
to  the  vineyard  when  the  vines  come  into  leaf.  A  few  may  be  destroyed 
or  starved,  and  the  efficiency  of  such  a  practice  as  plowing  and  sheep- 
ing will  depend  largely  upon  how  generally  it  is  carried  out  in  a 
district. 

To  kill  the  overwintering  hoppers  either  during  the  winter  or 
in  the  spring  when  they  first  come  onto  the  vines,  and  thus  destroy 
them  before  they  multiply  and  do  damage  would  be  the  best  solution 
of  hopper  control.  Thus  far,  however,  no  generally  satisfactory  method 
for  such  control  has  been  found.  A  three-sided  screen  box  operated 
to  capture  the  adults  on  the  vines  when  the  shoots  are  six  to  eight 
inches  long  has  been  used  with  success  in  many  cases,  but  it  is  not 
satisfactory  for  all  styles  of  vine  pruning,  and  involves  too  much 
hard  labor  to  suit  many  California  vineyardists.  Experiments  carried 
on  last  spring  in  spraying  into  a  canvas  canopy  attached  to  the  spray- 
rig  failed  to  kill  a  sufficient  percentage  of  the  adult  hoppers.  By  this 
apparatus  the  vine  and  the  whole  interior  of  the  canopy  was  thoroughly 
charged  with  the  spray,  but  the  winged  hoppers  proved  to  be  too 
resistant  to  any  of  the  materials  that  could  be  used  with  safety  to  the 


vine.  In  view  of  these  objections  to  the  control  of  the  adult  hoppers, 
spraying  for  the  young  or  nymphs  was  carried  on  later  in  the  season 
Spraying  for  the  Nymphs  or  Young. — As  will  be  noted  above,  the 
adult  hoppers  are  almost  impossible  to  kill  with  a  spray ;  on  the  other 
hand,  the  young  are  very  readily  killed  by  a  proper  spray.  The  chief 
difficulty  is  to  get  the  spray  on  the  under  side  of  all  the  leaves  where 
the  hoppers  are,  and  there  is  the  further  objection  that  many  of  the 
eggs  which  are  within  the  tissues  of  the  leaf,  as  well  as  the  adults, 
which  are  also  present,  are  not  affected  by  the  spray.  In  spite  of  these 
drawbacks,  however,  spraying  for  the  nymphs  will  pay  when  the 
hoppers  are  excessively  abundant.  The  destruction  of  the  young 
greatly  reduces  the  number  already  present,  as  well  as  the  succeeding 
generation. 

Materials. — A  number  of  different  sprays  were  tested,  but  only 
the  one  found  most  satisfactory  will  be  discussed  here.  The  spray 
found  most  efficient  in  killing  the  young,  as  well  as  most  neutral  to 
the  grape  foliage  and  berry,  was  blackleaf  40  per  cent  and  soap  in  the 
following  amounts : 

Blackleaf  40%  1  pint 

Liquid   soap %    gallon 

or 

Hard   soap 2   pounds 

Water  200  gallons 

If  liquid  soap  can  be  procured,  it  obviates  the  necessity  of  heating. 
The  hard  soap,  preferably  whale-oil,  is  cut  in  thin  slices  and  dissolved 
in  hot  water.  Where  soap  is  added  to  the  blackleaf  the  spray  carries 
and  spreads  better,  but  too  much  soap  should  not  be  used  or  a  spotting 
of  the  berries  will  occur. 

Equipment. — A  power  sprayer  is  very  desirable  for  hopper  spray- 
ing, though  if  the  acreage  be  small  a  hand  pump  will  suffice.  In  our 
work  last  season  a  large  capacity  orchard  sprayer  was  used,  as  well  as 
a  smaller  vineyard  sprayer,  as  shown  in  figure  2.  Since  the  ground 
is  usually  freshly  plowed  at  the  time  of  spraying,  too  heavy  an  outfit 
is  not  desirable,  and  a  short-turning  truck  is  needed.  A  supply  wagon 
for  carrying  materials  and  water  to  the  sprayer  in  the  field  is  econ- 
omical. Whatever  kind  of  spray  outfit  is  used,  it  will  be  found  con- 
venient to  take  several  rows  at  a  time  and  to  do  this  an  extension  of 
the  hose  above  the  vines  is  necessary.  In  the  figure  an  improvised 
arrangement  is  seen  which  simply  supports  the  spray  hose.  In  the 
place  of  this  a  gas-pipe  extension  may  be  employed  with  connections 
for  the  spray  hose  between  every  alternate  two  rows. 


The  most  satisfactory  type 
of  nozzle  is  an  angle  nozzle  with 
no  plunger  or  other  addition  to 
catch  among  the  canes.  An  angle 
Bean  mist  or  whirlpool,  or  a 
Friend  " Drive"  spray  nozzle  is 
suitable.  One  of  these  nozzles, 
or  two  if  desired,  is  attached  to 
a  rod  but  four  feet  long.  The 
ordinary  eight  or  ten  foot  rods 
for  orchard  spraying  cannot  be 
used  with  satisfaction  in  a  vine- 
yard. 

Applicatio  n. — Since  the 
young  hoppers  are  on  the  under 
side  of  the  leaves  entirely,  the 
spray  must  be  directed  from 
below.  It  is  not  necessary  to 
spray  the  upper  sides  of  the 
leaves.  The  spray  will  kill  no 
more  hoppers  than  are  hit  so  that 
the  results  will  depend  upon  the 
thoroughness  with  which  the 
application  is  made. 

Time  of  Application. — One 
of  the  most  important  factors  in 
hopper  spraying  is  the  time  of 
application.  If  the  spray  is  ap- 
plied too  early,  too  many  eggs 
which  have  not  yet  hatched  will 
escape  because  the  spray  cannot 
reach  them;  if  too  late,  many 
young  will  have  become  adult- 
winged  hoppers  which  cannot  be 
killed,  and  these  will  later  de- 
posit their  full  quota  of  eggs. 

For  the  Fresno  section  in 
average  years,  the  time  for  hop- 
per spraying  will  be  from  May 
20  to  about  June  10.  The 
criterion  to  go  by  for  each  year 
and  locality  is  to  begin  spraying 


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as  soon  as  some  of  the  nymphs  are  in  the  last  stage  as  shown  in 
figure  1  on  the  extreme  right.  The  wing-pads,  the  projections  extend- 
ing down  the  sides  of  the  body,  are  shown  to  be  of  considerable  length 
in  this  stage.  They  extend  to  the  fourth  ring  of  the  abdomen.  After 
five  days  in  this  stage,  they  emerge  with  fully  developed  wings.  Such 
hoppers  with  fully  developed  wings  cannot  be  killed  by  the  spray. 

Cost. — On  account  of  the  smaller  returns  per  acre  of  grapes  as 
compared  with  some  of  the  tree  fruit  crops,  the  cost  of  any  control 
work  to  be  practicable  must  be  kept  as  low  as  possible.  The  following 
figures  will  show  that  spraying  for  the  hoppers  is  not  exorbitant, 
especially  when  the  hoppers  are  extremely  abundant  and  the  con- 
sequent benefit  to  the  fruit  and  vine  is  taken  into  consideration. 

The  two  outfits  used  by  Mr.  P.  H.  McGarry  at  Clovis  consisted  of  a 
IV2  H.  P.  Bean  engine  pump  with  three  fifty-gallon  barrels  mounted 
on  a  wagon  truck.  There  were  four  lines  of  hose  per  outfit  and  a  single 
small  nozzle  throwing  a  fine  mist  spray  on  the  end  of  each  rod.  Such 
an  outfit  costs  about  $165.  There  were  five  men  in  the  crew,  one  team- 
ster and  four  nozzle  men.  One  of  these  outfits  sprayed  about  4500  vines 
per  day  (545  vines  per  acre)  or  8.22  acres  per  day.  The  vines  were 
seven-year-old  Malagas,  and  the  amount  of  spray  per  vine  was  approxi- 
mately one  quart.  This  spraying,  including  labor  and  materials,  cost 
from  $2.50  to  $4.50  per  acre. 

s 

Materials 

Blackleaf  40%,  1  pint  $  1.56 

Whale-oil  soap,  2  pounds  at  $.06  12 

Cost  of  material  per  200  gallons  of  spray  $  1.68 

Labor 

1    man   and   team   $  4.50 

4  nozzle  men  at  $2.00  8.00 

Cost  of  labor  per  day $12.50 

On  Mr.  J.  H.  Jack's  place  at  Parlier,  a  Bean  Giant  Duplex  2% 
H.  P.  outfit  with  a  tank  holding  two  hundred  gallons  was  used.  Mr. 
Jack  estimated  that  with  one  teamster,  two  nozzle  men,  and  an  extra 
team  and  teamster  for  a  supply  wagon,  he  could  spray  10  acres  per 
day  at  a  cost  of  $3.30  per  acre.  The  vines  on  this  place  were  twenty- 
four-year-old  muscats  but  were  about  the  same  size  as  the  seven-year- 
old  Malagas  on  Mr.  McGarry 's  place.  In  most  of  the  spraying  on  Mr. 
Jack's  vines,  about  two-thirds  of  a  gallon  per  vine  was  used,  and 
it  requires  about  this  amount  for  good  work  on  that  size  of  vine. 


On  the  basis,  therefore,  of  two-thirds  of  a  gallon  per  vine  for 
twenty-four-year-old  muscats  or  eight  or  ten-year-old  Malagas,  and 
counting  500  vines  per  acre,  the  amount  of  material  required  to  spray 
10  acres  would  be  as  follows : 

5,000  vines  at  %  gallon  3, 333%  gallons  of  spray 

Blackleaf  40%  at  1  pint  to  200  gallons  

16%    pints    or    about    2    gallons 

Whale-oil  soap  at  2  pounds  to  200  gallons  33  %  pounds 


Fig.  2. — A  vineyard  sprayer  used  in  spraying  for  the  grape  leaf-hopper.  The 
temporary  support  of  the  hose  may  be  replaced  by  gas-pipe  extension  with  hose 
connections. 


The  cost  of  the  above  material  for  10  acres  would  be  as  follows : 

Blackleaf,  40%,  2  gallons  at  $12.50  per  gallon  $25.00 

Whale-oil  soap,  33%  pounds  at  $.06  per  pound  2.00 


Total  cost  materials  for  10  acres 


$27.00 


When  the  materials  are  purchased  in  quantity,  the  cost  should  be 
less  than  is  indicated  above. 


STATION    PUBLICATIONS    AVAILABLE    FOR    DISTRIBUTION 


REPORTS 


Appendix   to   Viticultural 


1897.      Resistant  Vines,  their  Selection,   Adaptation,   and  Grafting 
Report  for  1896. 

1902.  Report  of  the  Agricultural   Experiment   Station  for   1898-1901. 

1903.  Report  of  the  Agricultural   Experiment   Station  for   1901-03. 

1904.  Twenty-second  Report  of  the  Agricultural  Experiment  Station-for  1903-04. 
1914.      Report  of  the   College  of  Agriculture   and  the  Agricultural   Experiment   Station, 

1913-June,    1914. 


July, 


No. 
168. 

169. 
170. 
174. 

177. 

178. 
182. 

183. 
184. 

185. 

195. 
197. 


198. 
203. 


207. 
208. 


Observations    on    Some   Vine    Diseases 

in    Sonoma  County. 
Tolerance  of  the  Sugar  Beet  for  Alkali. 
Studies  in  Grasshopper  Control. 
A  New  Wine-Cooling  Machine. 
A    New    Method    of    Making   Dry    Red 

Wine. 
Mosquito  Control. 
Analysis    of    Paris    Green    and    Lead 

Arsenate.     Proposed  Insecticide  Law. 
The  California  Tussock-Moth. 
Report    of    the    Plant    Pathologist    to 

July  1,   1906. 
Report  of  Progress  in   Cereal  Investi- 
gations. 
The  California  Grape  Root-worm. 
Grape  Culture  in  California  ;  Improved 

Methods     of     Wine-making;      Yeast 

from  California  Grapes. 
The  Grape  Leaf-Hopper. 
Report    of    the    Plant    Pathologist    to 

July  1,    1909. 
The  Control  of  the  Argentine   Ant. 
The  Late  Blight  of  Celery. 


BULLETINS 
No. 
211. 


212. 
213. 
216. 


225. 
227. 
230. 
234. 
240. 
241. 
242. 
243. 

244. 
245. 
246. 
248. 

249. 
250. 


How  to   Increase  the   Yield   of   Wheat 

in  California^ 
Califoprfa  White  Wheats. 
ThgCPrinciples  of  Wine-making. 
A    Progress    Report    upon    Soil    and 

Climatic     Factors     Influencing    the 

Composition  of  Wheat. 
Tolerance  of  Eucalyptus  for  Alkali. 
Grape  Vinegar. 
Enological  Investigations. 
Red  Spiders  and  Mites  of  Citrus  Trees. 
Commercial  Fertilizers. 
Vine  Pruning  in  California.     Part  I. 
Humus  in   California   Soils. 
The  Intradermal  Test  for  Tuberculosis 

in  Cattle  and  Hogs. 
Utilization  of  Waste  Oranges. 
Commercial  Fertilizers. . 
Vine  Pruning  in  California.     Part  II. 
The  Economic  Value  of  Pacific   Coast 

Kelps. 
Stock  Poisoning  Plants  of  California. 
The  Loquat. 


No. 
65. 
68. 
69. 
70. 

76. 
79. 
80. 
82. 

83. 
84. 
87. 
88. 


100. 
101. 


102. 
106. 


107. 


CIRCULARS 

No. 
The  California   Insecticide  Law.  108. 

The  Prevention  of  Hog  Cholera.  109. 

The  Extermination  of  Morning-Glory. 
Observations   on   the    Status   of   Corn 

Growing  in  California.  110. 

Hot  Room  Callusing.  111. 

List  of  Insecticide  Dealers 

Boys'    and   Girls'   Clubs.  113. 

The    Common     Ground     Squirrels     of  114. 

California.  115. 

Potato  Growing  Clubs.  116. 

Mushrooms  and  Toadstools.  117. 

Alfalfa. 
Advantages  to  the  Breeder  in   Testing  118. 

his  Pure-bred  Cows  for  the  Register  119. 

of  Merit.  120. 

Disinfection  on  the  Farm. 
Infectious    Abortion    and    Sterility    in  121. 

Cows. 
Pruning  Frosted  Citrus  Trees.  122. 

Codling    Moth    Control    in    the    Sacra- 
mento Valley.  123. 
The  Woolly  Aphis. 
Directions  for  using  Anti-Hog-Cholera               124. 

Serum.  125. 

Spraying  Walnut  Trees  for  Blight  and 

Aphis  Control. 


Grape  Juice. 

Community  or  Local  Extension  Work 
by  the  High  School  Agricultural  De- 
partment. 

Green  Manuring  in  California. 

The  Use  of  Lime  and  Gypsum  on  Cali- 
fornia Soils. 

Correspondence  Courses  in  Agriculture. 

Increasing  the  Duty  of  Water. 

Grafting  Vinifera  Vineyards. 

Silk  Worm  Experiments. 

The  Selection  and  Cost  of  a  Small 
Pumping  Plant. 

The  County  Farm  Bureau. 

Winery  Directions. 

Potato  Growing  in  the  San  Joaquin 
and  Sacramento  Deltas  of  California. 

Some  Things  the  Prospective  Settler 
Should  Know. 

The  Management  of  Strawberry  Soils 
in  Pajaro  Valley. 

Fundamental  Principles  of  Co-opera- 
tion in  Agriculture. 

Alfalfa  Silage  for  Fattening  Steers. 

Aphids  on  Grain  and  Cantaloupes. 


